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TOMOYO Linux Cross Reference
Linux/net/sunrpc/auth.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * linux/net/sunrpc/auth.c
  4  *
  5  * Generic RPC client authentication API.
  6  *
  7  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
  8  */
  9 
 10 #include <linux/types.h>
 11 #include <linux/sched.h>
 12 #include <linux/cred.h>
 13 #include <linux/module.h>
 14 #include <linux/slab.h>
 15 #include <linux/errno.h>
 16 #include <linux/hash.h>
 17 #include <linux/sunrpc/clnt.h>
 18 #include <linux/sunrpc/gss_api.h>
 19 #include <linux/spinlock.h>
 20 
 21 #include <trace/events/sunrpc.h>
 22 
 23 #define RPC_CREDCACHE_DEFAULT_HASHBITS  (4)
 24 struct rpc_cred_cache {
 25         struct hlist_head       *hashtable;
 26         unsigned int            hashbits;
 27         spinlock_t              lock;
 28 };
 29 
 30 static unsigned int auth_hashbits = RPC_CREDCACHE_DEFAULT_HASHBITS;
 31 
 32 static const struct rpc_authops __rcu *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
 33         [RPC_AUTH_NULL] = (const struct rpc_authops __force __rcu *)&authnull_ops,
 34         [RPC_AUTH_UNIX] = (const struct rpc_authops __force __rcu *)&authunix_ops,
 35         [RPC_AUTH_TLS]  = (const struct rpc_authops __force __rcu *)&authtls_ops,
 36 };
 37 
 38 static LIST_HEAD(cred_unused);
 39 static unsigned long number_cred_unused;
 40 
 41 static struct cred machine_cred = {
 42         .usage = ATOMIC_INIT(1),
 43 };
 44 
 45 /*
 46  * Return the machine_cred pointer to be used whenever
 47  * the a generic machine credential is needed.
 48  */
 49 const struct cred *rpc_machine_cred(void)
 50 {
 51         return &machine_cred;
 52 }
 53 EXPORT_SYMBOL_GPL(rpc_machine_cred);
 54 
 55 #define MAX_HASHTABLE_BITS (14)
 56 static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
 57 {
 58         unsigned long num;
 59         unsigned int nbits;
 60         int ret;
 61 
 62         if (!val)
 63                 goto out_inval;
 64         ret = kstrtoul(val, 0, &num);
 65         if (ret)
 66                 goto out_inval;
 67         nbits = fls(num - 1);
 68         if (nbits > MAX_HASHTABLE_BITS || nbits < 2)
 69                 goto out_inval;
 70         *(unsigned int *)kp->arg = nbits;
 71         return 0;
 72 out_inval:
 73         return -EINVAL;
 74 }
 75 
 76 static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
 77 {
 78         unsigned int nbits;
 79 
 80         nbits = *(unsigned int *)kp->arg;
 81         return sprintf(buffer, "%u\n", 1U << nbits);
 82 }
 83 
 84 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
 85 
 86 static const struct kernel_param_ops param_ops_hashtbl_sz = {
 87         .set = param_set_hashtbl_sz,
 88         .get = param_get_hashtbl_sz,
 89 };
 90 
 91 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
 92 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
 93 
 94 static unsigned long auth_max_cred_cachesize = ULONG_MAX;
 95 module_param(auth_max_cred_cachesize, ulong, 0644);
 96 MODULE_PARM_DESC(auth_max_cred_cachesize, "RPC credential maximum total cache size");
 97 
 98 static u32
 99 pseudoflavor_to_flavor(u32 flavor) {
100         if (flavor > RPC_AUTH_MAXFLAVOR)
101                 return RPC_AUTH_GSS;
102         return flavor;
103 }
104 
105 int
106 rpcauth_register(const struct rpc_authops *ops)
107 {
108         const struct rpc_authops *old;
109         rpc_authflavor_t flavor;
110 
111         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
112                 return -EINVAL;
113         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], NULL, ops);
114         if (old == NULL || old == ops)
115                 return 0;
116         return -EPERM;
117 }
118 EXPORT_SYMBOL_GPL(rpcauth_register);
119 
120 int
121 rpcauth_unregister(const struct rpc_authops *ops)
122 {
123         const struct rpc_authops *old;
124         rpc_authflavor_t flavor;
125 
126         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
127                 return -EINVAL;
128 
129         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], ops, NULL);
130         if (old == ops || old == NULL)
131                 return 0;
132         return -EPERM;
133 }
134 EXPORT_SYMBOL_GPL(rpcauth_unregister);
135 
136 static const struct rpc_authops *
137 rpcauth_get_authops(rpc_authflavor_t flavor)
138 {
139         const struct rpc_authops *ops;
140 
141         if (flavor >= RPC_AUTH_MAXFLAVOR)
142                 return NULL;
143 
144         rcu_read_lock();
145         ops = rcu_dereference(auth_flavors[flavor]);
146         if (ops == NULL) {
147                 rcu_read_unlock();
148                 request_module("rpc-auth-%u", flavor);
149                 rcu_read_lock();
150                 ops = rcu_dereference(auth_flavors[flavor]);
151                 if (ops == NULL)
152                         goto out;
153         }
154         if (!try_module_get(ops->owner))
155                 ops = NULL;
156 out:
157         rcu_read_unlock();
158         return ops;
159 }
160 
161 static void
162 rpcauth_put_authops(const struct rpc_authops *ops)
163 {
164         module_put(ops->owner);
165 }
166 
167 /**
168  * rpcauth_get_pseudoflavor - check if security flavor is supported
169  * @flavor: a security flavor
170  * @info: a GSS mech OID, quality of protection, and service value
171  *
172  * Verifies that an appropriate kernel module is available or already loaded.
173  * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is
174  * not supported locally.
175  */
176 rpc_authflavor_t
177 rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info)
178 {
179         const struct rpc_authops *ops = rpcauth_get_authops(flavor);
180         rpc_authflavor_t pseudoflavor;
181 
182         if (!ops)
183                 return RPC_AUTH_MAXFLAVOR;
184         pseudoflavor = flavor;
185         if (ops->info2flavor != NULL)
186                 pseudoflavor = ops->info2flavor(info);
187 
188         rpcauth_put_authops(ops);
189         return pseudoflavor;
190 }
191 EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor);
192 
193 /**
194  * rpcauth_get_gssinfo - find GSS tuple matching a GSS pseudoflavor
195  * @pseudoflavor: GSS pseudoflavor to match
196  * @info: rpcsec_gss_info structure to fill in
197  *
198  * Returns zero and fills in "info" if pseudoflavor matches a
199  * supported mechanism.
200  */
201 int
202 rpcauth_get_gssinfo(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info)
203 {
204         rpc_authflavor_t flavor = pseudoflavor_to_flavor(pseudoflavor);
205         const struct rpc_authops *ops;
206         int result;
207 
208         ops = rpcauth_get_authops(flavor);
209         if (ops == NULL)
210                 return -ENOENT;
211 
212         result = -ENOENT;
213         if (ops->flavor2info != NULL)
214                 result = ops->flavor2info(pseudoflavor, info);
215 
216         rpcauth_put_authops(ops);
217         return result;
218 }
219 EXPORT_SYMBOL_GPL(rpcauth_get_gssinfo);
220 
221 struct rpc_auth *
222 rpcauth_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
223 {
224         struct rpc_auth *auth = ERR_PTR(-EINVAL);
225         const struct rpc_authops *ops;
226         u32 flavor = pseudoflavor_to_flavor(args->pseudoflavor);
227 
228         ops = rpcauth_get_authops(flavor);
229         if (ops == NULL)
230                 goto out;
231 
232         auth = ops->create(args, clnt);
233 
234         rpcauth_put_authops(ops);
235         if (IS_ERR(auth))
236                 return auth;
237         if (clnt->cl_auth)
238                 rpcauth_release(clnt->cl_auth);
239         clnt->cl_auth = auth;
240 
241 out:
242         return auth;
243 }
244 EXPORT_SYMBOL_GPL(rpcauth_create);
245 
246 void
247 rpcauth_release(struct rpc_auth *auth)
248 {
249         if (!refcount_dec_and_test(&auth->au_count))
250                 return;
251         auth->au_ops->destroy(auth);
252 }
253 
254 static DEFINE_SPINLOCK(rpc_credcache_lock);
255 
256 /*
257  * On success, the caller is responsible for freeing the reference
258  * held by the hashtable
259  */
260 static bool
261 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
262 {
263         if (!test_and_clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
264                 return false;
265         hlist_del_rcu(&cred->cr_hash);
266         return true;
267 }
268 
269 static bool
270 rpcauth_unhash_cred(struct rpc_cred *cred)
271 {
272         spinlock_t *cache_lock;
273         bool ret;
274 
275         if (!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
276                 return false;
277         cache_lock = &cred->cr_auth->au_credcache->lock;
278         spin_lock(cache_lock);
279         ret = rpcauth_unhash_cred_locked(cred);
280         spin_unlock(cache_lock);
281         return ret;
282 }
283 
284 /*
285  * Initialize RPC credential cache
286  */
287 int
288 rpcauth_init_credcache(struct rpc_auth *auth)
289 {
290         struct rpc_cred_cache *new;
291         unsigned int hashsize;
292 
293         new = kmalloc(sizeof(*new), GFP_KERNEL);
294         if (!new)
295                 goto out_nocache;
296         new->hashbits = auth_hashbits;
297         hashsize = 1U << new->hashbits;
298         new->hashtable = kcalloc(hashsize, sizeof(new->hashtable[0]), GFP_KERNEL);
299         if (!new->hashtable)
300                 goto out_nohashtbl;
301         spin_lock_init(&new->lock);
302         auth->au_credcache = new;
303         return 0;
304 out_nohashtbl:
305         kfree(new);
306 out_nocache:
307         return -ENOMEM;
308 }
309 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
310 
311 char *
312 rpcauth_stringify_acceptor(struct rpc_cred *cred)
313 {
314         if (!cred->cr_ops->crstringify_acceptor)
315                 return NULL;
316         return cred->cr_ops->crstringify_acceptor(cred);
317 }
318 EXPORT_SYMBOL_GPL(rpcauth_stringify_acceptor);
319 
320 /*
321  * Destroy a list of credentials
322  */
323 static inline
324 void rpcauth_destroy_credlist(struct list_head *head)
325 {
326         struct rpc_cred *cred;
327 
328         while (!list_empty(head)) {
329                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
330                 list_del_init(&cred->cr_lru);
331                 put_rpccred(cred);
332         }
333 }
334 
335 static void
336 rpcauth_lru_add_locked(struct rpc_cred *cred)
337 {
338         if (!list_empty(&cred->cr_lru))
339                 return;
340         number_cred_unused++;
341         list_add_tail(&cred->cr_lru, &cred_unused);
342 }
343 
344 static void
345 rpcauth_lru_add(struct rpc_cred *cred)
346 {
347         if (!list_empty(&cred->cr_lru))
348                 return;
349         spin_lock(&rpc_credcache_lock);
350         rpcauth_lru_add_locked(cred);
351         spin_unlock(&rpc_credcache_lock);
352 }
353 
354 static void
355 rpcauth_lru_remove_locked(struct rpc_cred *cred)
356 {
357         if (list_empty(&cred->cr_lru))
358                 return;
359         number_cred_unused--;
360         list_del_init(&cred->cr_lru);
361 }
362 
363 static void
364 rpcauth_lru_remove(struct rpc_cred *cred)
365 {
366         if (list_empty(&cred->cr_lru))
367                 return;
368         spin_lock(&rpc_credcache_lock);
369         rpcauth_lru_remove_locked(cred);
370         spin_unlock(&rpc_credcache_lock);
371 }
372 
373 /*
374  * Clear the RPC credential cache, and delete those credentials
375  * that are not referenced.
376  */
377 void
378 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
379 {
380         LIST_HEAD(free);
381         struct hlist_head *head;
382         struct rpc_cred *cred;
383         unsigned int hashsize = 1U << cache->hashbits;
384         int             i;
385 
386         spin_lock(&rpc_credcache_lock);
387         spin_lock(&cache->lock);
388         for (i = 0; i < hashsize; i++) {
389                 head = &cache->hashtable[i];
390                 while (!hlist_empty(head)) {
391                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
392                         rpcauth_unhash_cred_locked(cred);
393                         /* Note: We now hold a reference to cred */
394                         rpcauth_lru_remove_locked(cred);
395                         list_add_tail(&cred->cr_lru, &free);
396                 }
397         }
398         spin_unlock(&cache->lock);
399         spin_unlock(&rpc_credcache_lock);
400         rpcauth_destroy_credlist(&free);
401 }
402 
403 /*
404  * Destroy the RPC credential cache
405  */
406 void
407 rpcauth_destroy_credcache(struct rpc_auth *auth)
408 {
409         struct rpc_cred_cache *cache = auth->au_credcache;
410 
411         if (cache) {
412                 auth->au_credcache = NULL;
413                 rpcauth_clear_credcache(cache);
414                 kfree(cache->hashtable);
415                 kfree(cache);
416         }
417 }
418 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
419 
420 
421 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
422 
423 /*
424  * Remove stale credentials. Avoid sleeping inside the loop.
425  */
426 static long
427 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
428 {
429         struct rpc_cred *cred, *next;
430         unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
431         long freed = 0;
432 
433         list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
434 
435                 if (nr_to_scan-- == 0)
436                         break;
437                 if (refcount_read(&cred->cr_count) > 1) {
438                         rpcauth_lru_remove_locked(cred);
439                         continue;
440                 }
441                 /*
442                  * Enforce a 60 second garbage collection moratorium
443                  * Note that the cred_unused list must be time-ordered.
444                  */
445                 if (time_in_range(cred->cr_expire, expired, jiffies))
446                         continue;
447                 if (!rpcauth_unhash_cred(cred))
448                         continue;
449 
450                 rpcauth_lru_remove_locked(cred);
451                 freed++;
452                 list_add_tail(&cred->cr_lru, free);
453         }
454         return freed ? freed : SHRINK_STOP;
455 }
456 
457 static unsigned long
458 rpcauth_cache_do_shrink(int nr_to_scan)
459 {
460         LIST_HEAD(free);
461         unsigned long freed;
462 
463         spin_lock(&rpc_credcache_lock);
464         freed = rpcauth_prune_expired(&free, nr_to_scan);
465         spin_unlock(&rpc_credcache_lock);
466         rpcauth_destroy_credlist(&free);
467 
468         return freed;
469 }
470 
471 /*
472  * Run memory cache shrinker.
473  */
474 static unsigned long
475 rpcauth_cache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
476 
477 {
478         if ((sc->gfp_mask & GFP_KERNEL) != GFP_KERNEL)
479                 return SHRINK_STOP;
480 
481         /* nothing left, don't come back */
482         if (list_empty(&cred_unused))
483                 return SHRINK_STOP;
484 
485         return rpcauth_cache_do_shrink(sc->nr_to_scan);
486 }
487 
488 static unsigned long
489 rpcauth_cache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
490 
491 {
492         return number_cred_unused * sysctl_vfs_cache_pressure / 100;
493 }
494 
495 static void
496 rpcauth_cache_enforce_limit(void)
497 {
498         unsigned long diff;
499         unsigned int nr_to_scan;
500 
501         if (number_cred_unused <= auth_max_cred_cachesize)
502                 return;
503         diff = number_cred_unused - auth_max_cred_cachesize;
504         nr_to_scan = 100;
505         if (diff < nr_to_scan)
506                 nr_to_scan = diff;
507         rpcauth_cache_do_shrink(nr_to_scan);
508 }
509 
510 /*
511  * Look up a process' credentials in the authentication cache
512  */
513 struct rpc_cred *
514 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
515                 int flags, gfp_t gfp)
516 {
517         LIST_HEAD(free);
518         struct rpc_cred_cache *cache = auth->au_credcache;
519         struct rpc_cred *cred = NULL,
520                         *entry, *new;
521         unsigned int nr;
522 
523         nr = auth->au_ops->hash_cred(acred, cache->hashbits);
524 
525         rcu_read_lock();
526         hlist_for_each_entry_rcu(entry, &cache->hashtable[nr], cr_hash) {
527                 if (!entry->cr_ops->crmatch(acred, entry, flags))
528                         continue;
529                 cred = get_rpccred(entry);
530                 if (cred)
531                         break;
532         }
533         rcu_read_unlock();
534 
535         if (cred != NULL)
536                 goto found;
537 
538         new = auth->au_ops->crcreate(auth, acred, flags, gfp);
539         if (IS_ERR(new)) {
540                 cred = new;
541                 goto out;
542         }
543 
544         spin_lock(&cache->lock);
545         hlist_for_each_entry(entry, &cache->hashtable[nr], cr_hash) {
546                 if (!entry->cr_ops->crmatch(acred, entry, flags))
547                         continue;
548                 cred = get_rpccred(entry);
549                 if (cred)
550                         break;
551         }
552         if (cred == NULL) {
553                 cred = new;
554                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
555                 refcount_inc(&cred->cr_count);
556                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
557         } else
558                 list_add_tail(&new->cr_lru, &free);
559         spin_unlock(&cache->lock);
560         rpcauth_cache_enforce_limit();
561 found:
562         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
563             cred->cr_ops->cr_init != NULL &&
564             !(flags & RPCAUTH_LOOKUP_NEW)) {
565                 int res = cred->cr_ops->cr_init(auth, cred);
566                 if (res < 0) {
567                         put_rpccred(cred);
568                         cred = ERR_PTR(res);
569                 }
570         }
571         rpcauth_destroy_credlist(&free);
572 out:
573         return cred;
574 }
575 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
576 
577 struct rpc_cred *
578 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
579 {
580         struct auth_cred acred;
581         struct rpc_cred *ret;
582         const struct cred *cred = current_cred();
583 
584         memset(&acred, 0, sizeof(acred));
585         acred.cred = cred;
586         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
587         return ret;
588 }
589 EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
590 
591 void
592 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
593                   struct rpc_auth *auth, const struct rpc_credops *ops)
594 {
595         INIT_HLIST_NODE(&cred->cr_hash);
596         INIT_LIST_HEAD(&cred->cr_lru);
597         refcount_set(&cred->cr_count, 1);
598         cred->cr_auth = auth;
599         cred->cr_flags = 0;
600         cred->cr_ops = ops;
601         cred->cr_expire = jiffies;
602         cred->cr_cred = get_cred(acred->cred);
603 }
604 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
605 
606 static struct rpc_cred *
607 rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
608 {
609         struct rpc_auth *auth = task->tk_client->cl_auth;
610         struct auth_cred acred = {
611                 .cred = get_task_cred(&init_task),
612         };
613         struct rpc_cred *ret;
614 
615         if (RPC_IS_ASYNC(task))
616                 lookupflags |= RPCAUTH_LOOKUP_ASYNC;
617         ret = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
618         put_cred(acred.cred);
619         return ret;
620 }
621 
622 static struct rpc_cred *
623 rpcauth_bind_machine_cred(struct rpc_task *task, int lookupflags)
624 {
625         struct rpc_auth *auth = task->tk_client->cl_auth;
626         struct auth_cred acred = {
627                 .principal = task->tk_client->cl_principal,
628                 .cred = init_task.cred,
629         };
630 
631         if (!acred.principal)
632                 return NULL;
633         if (RPC_IS_ASYNC(task))
634                 lookupflags |= RPCAUTH_LOOKUP_ASYNC;
635         return auth->au_ops->lookup_cred(auth, &acred, lookupflags);
636 }
637 
638 static struct rpc_cred *
639 rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
640 {
641         struct rpc_auth *auth = task->tk_client->cl_auth;
642 
643         return rpcauth_lookupcred(auth, lookupflags);
644 }
645 
646 static int
647 rpcauth_bindcred(struct rpc_task *task, const struct cred *cred, int flags)
648 {
649         struct rpc_rqst *req = task->tk_rqstp;
650         struct rpc_cred *new = NULL;
651         int lookupflags = 0;
652         struct rpc_auth *auth = task->tk_client->cl_auth;
653         struct auth_cred acred = {
654                 .cred = cred,
655         };
656 
657         if (flags & RPC_TASK_ASYNC)
658                 lookupflags |= RPCAUTH_LOOKUP_NEW | RPCAUTH_LOOKUP_ASYNC;
659         if (task->tk_op_cred)
660                 /* Task must use exactly this rpc_cred */
661                 new = get_rpccred(task->tk_op_cred);
662         else if (cred != NULL && cred != &machine_cred)
663                 new = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
664         else if (cred == &machine_cred)
665                 new = rpcauth_bind_machine_cred(task, lookupflags);
666 
667         /* If machine cred couldn't be bound, try a root cred */
668         if (new)
669                 ;
670         else if (cred == &machine_cred)
671                 new = rpcauth_bind_root_cred(task, lookupflags);
672         else if (flags & RPC_TASK_NULLCREDS)
673                 new = authnull_ops.lookup_cred(NULL, NULL, 0);
674         else
675                 new = rpcauth_bind_new_cred(task, lookupflags);
676         if (IS_ERR(new))
677                 return PTR_ERR(new);
678         put_rpccred(req->rq_cred);
679         req->rq_cred = new;
680         return 0;
681 }
682 
683 void
684 put_rpccred(struct rpc_cred *cred)
685 {
686         if (cred == NULL)
687                 return;
688         rcu_read_lock();
689         if (refcount_dec_and_test(&cred->cr_count))
690                 goto destroy;
691         if (refcount_read(&cred->cr_count) != 1 ||
692             !test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
693                 goto out;
694         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
695                 cred->cr_expire = jiffies;
696                 rpcauth_lru_add(cred);
697                 /* Race breaker */
698                 if (unlikely(!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)))
699                         rpcauth_lru_remove(cred);
700         } else if (rpcauth_unhash_cred(cred)) {
701                 rpcauth_lru_remove(cred);
702                 if (refcount_dec_and_test(&cred->cr_count))
703                         goto destroy;
704         }
705 out:
706         rcu_read_unlock();
707         return;
708 destroy:
709         rcu_read_unlock();
710         cred->cr_ops->crdestroy(cred);
711 }
712 EXPORT_SYMBOL_GPL(put_rpccred);
713 
714 /**
715  * rpcauth_marshcred - Append RPC credential to end of @xdr
716  * @task: controlling RPC task
717  * @xdr: xdr_stream containing initial portion of RPC Call header
718  *
719  * On success, an appropriate verifier is added to @xdr, @xdr is
720  * updated to point past the verifier, and zero is returned.
721  * Otherwise, @xdr is in an undefined state and a negative errno
722  * is returned.
723  */
724 int rpcauth_marshcred(struct rpc_task *task, struct xdr_stream *xdr)
725 {
726         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
727 
728         return ops->crmarshal(task, xdr);
729 }
730 
731 /**
732  * rpcauth_wrap_req_encode - XDR encode the RPC procedure
733  * @task: controlling RPC task
734  * @xdr: stream where on-the-wire bytes are to be marshalled
735  *
736  * On success, @xdr contains the encoded and wrapped message.
737  * Otherwise, @xdr is in an undefined state.
738  */
739 int rpcauth_wrap_req_encode(struct rpc_task *task, struct xdr_stream *xdr)
740 {
741         kxdreproc_t encode = task->tk_msg.rpc_proc->p_encode;
742 
743         encode(task->tk_rqstp, xdr, task->tk_msg.rpc_argp);
744         return 0;
745 }
746 EXPORT_SYMBOL_GPL(rpcauth_wrap_req_encode);
747 
748 /**
749  * rpcauth_wrap_req - XDR encode and wrap the RPC procedure
750  * @task: controlling RPC task
751  * @xdr: stream where on-the-wire bytes are to be marshalled
752  *
753  * On success, @xdr contains the encoded and wrapped message,
754  * and zero is returned. Otherwise, @xdr is in an undefined
755  * state and a negative errno is returned.
756  */
757 int rpcauth_wrap_req(struct rpc_task *task, struct xdr_stream *xdr)
758 {
759         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
760 
761         return ops->crwrap_req(task, xdr);
762 }
763 
764 /**
765  * rpcauth_checkverf - Validate verifier in RPC Reply header
766  * @task: controlling RPC task
767  * @xdr: xdr_stream containing RPC Reply header
768  *
769  * Return values:
770  *   %0: Verifier is valid. @xdr now points past the verifier.
771  *   %-EIO: Verifier is corrupted or message ended early.
772  *   %-EACCES: Verifier is intact but not valid.
773  *   %-EPROTONOSUPPORT: Server does not support the requested auth type.
774  *
775  * When a negative errno is returned, @xdr is left in an undefined
776  * state.
777  */
778 int
779 rpcauth_checkverf(struct rpc_task *task, struct xdr_stream *xdr)
780 {
781         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
782 
783         return ops->crvalidate(task, xdr);
784 }
785 
786 /**
787  * rpcauth_unwrap_resp_decode - Invoke XDR decode function
788  * @task: controlling RPC task
789  * @xdr: stream where the Reply message resides
790  *
791  * Returns zero on success; otherwise a negative errno is returned.
792  */
793 int
794 rpcauth_unwrap_resp_decode(struct rpc_task *task, struct xdr_stream *xdr)
795 {
796         kxdrdproc_t decode = task->tk_msg.rpc_proc->p_decode;
797 
798         return decode(task->tk_rqstp, xdr, task->tk_msg.rpc_resp);
799 }
800 EXPORT_SYMBOL_GPL(rpcauth_unwrap_resp_decode);
801 
802 /**
803  * rpcauth_unwrap_resp - Invoke unwrap and decode function for the cred
804  * @task: controlling RPC task
805  * @xdr: stream where the Reply message resides
806  *
807  * Returns zero on success; otherwise a negative errno is returned.
808  */
809 int
810 rpcauth_unwrap_resp(struct rpc_task *task, struct xdr_stream *xdr)
811 {
812         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
813 
814         return ops->crunwrap_resp(task, xdr);
815 }
816 
817 bool
818 rpcauth_xmit_need_reencode(struct rpc_task *task)
819 {
820         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
821 
822         if (!cred || !cred->cr_ops->crneed_reencode)
823                 return false;
824         return cred->cr_ops->crneed_reencode(task);
825 }
826 
827 int
828 rpcauth_refreshcred(struct rpc_task *task)
829 {
830         struct rpc_cred *cred;
831         int err;
832 
833         cred = task->tk_rqstp->rq_cred;
834         if (cred == NULL) {
835                 err = rpcauth_bindcred(task, task->tk_msg.rpc_cred, task->tk_flags);
836                 if (err < 0)
837                         goto out;
838                 cred = task->tk_rqstp->rq_cred;
839         }
840 
841         err = cred->cr_ops->crrefresh(task);
842 out:
843         if (err < 0)
844                 task->tk_status = err;
845         return err;
846 }
847 
848 void
849 rpcauth_invalcred(struct rpc_task *task)
850 {
851         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
852 
853         if (cred)
854                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
855 }
856 
857 int
858 rpcauth_uptodatecred(struct rpc_task *task)
859 {
860         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
861 
862         return cred == NULL ||
863                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
864 }
865 
866 static struct shrinker *rpc_cred_shrinker;
867 
868 int __init rpcauth_init_module(void)
869 {
870         int err;
871 
872         err = rpc_init_authunix();
873         if (err < 0)
874                 goto out1;
875         rpc_cred_shrinker = shrinker_alloc(0, "sunrpc_cred");
876         if (!rpc_cred_shrinker) {
877                 err = -ENOMEM;
878                 goto out2;
879         }
880 
881         rpc_cred_shrinker->count_objects = rpcauth_cache_shrink_count;
882         rpc_cred_shrinker->scan_objects = rpcauth_cache_shrink_scan;
883 
884         shrinker_register(rpc_cred_shrinker);
885 
886         return 0;
887 out2:
888         rpc_destroy_authunix();
889 out1:
890         return err;
891 }
892 
893 void rpcauth_remove_module(void)
894 {
895         rpc_destroy_authunix();
896         shrinker_free(rpc_cred_shrinker);
897 }
898 

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